Geographic variation of golden redfish (Sebastes marinus) and deep-sea redfish (S. mentella) in the North Atlantic based on otolith shape analysis

The unresolved interrelationships of North Atlantic redfish stocks have prevented adaptive fisheries assessment and management in the past. Otolith shapes of golden redfish (S. marinus) and deep-sea redfish (S. mentella) were analysed for geographic variation within the entire distribution range in the North Atlantic, in order to evaluate this technique for stock separation. Multivariate analysis of elliptical Fourier shape descriptors revealed high similarity of S. marinus within the central North Atlantic areas (West and East Greenland, Iceland) that were relatively well separated from the Flemish Cap and Barents Sea samples. A similar separation of the Barents Sea area was also observed for S. mentella, whereas the western (Flemish Cap, Davis Strait) and central areas were overlapping to a greater extent. The overall classification rate given by discriminant analysis was poor for both species (<50%) but increased to 72–74% by combining sampling areas to regions (west, central, east). Geographic variation in otolith shapes of both redfish species suggests a separation of the Northeast Arctic stocks (Barents Sea) of both species from the other redfish stocks assessed within ICES and NAFO, whereas similarities observed for the highly migratory S. mentella give reason for integrated management of demersal and pelagic occurrences of this important fisheries resource that straddles the ICES/NAFO boundaries.